1. Field of the Invention
This invention relates generally to the recording and reproducing of information signals, such as, video signals, and more particularly is directed to the processing of such video signal so as to avoid waveform distortions thereof when magnetically recorded and reproduced.
2. Description of the Prior Art
In the recording and reproducing of video signals on magnetic tape or the like, it is well known to record the entire video signal, in the case of a monochrome or black-and-white signal, or the luminance component, in the case of a color video signal, as a frequency modulation of a relatively high frequency carrier. Further, in such recording, a high frequency portion of the video signal, which hereinafter is intended to mean either the entire monochrome video signal or the luminance component of a color video signal is pre-emphasized in a pre-emphasis circuit prior to the frequency modulation of the carrier therewith, and, in the reproducing or playback operation, the reproduced frequency modulated video signal is demodulated and then subjected to a de-emphasis which is complementary to the original pre-emphasis for reducing the so-called FM noise in the demodulated video signal. However, the pre-emphasis for improving the signal-to-noise ratio in respect to the FM noise results in overshoots, particularly at portions of the video signal where the level thereof is abruptly changed. If the pre-emphasized video signal with such large overshoots is employed as the modulating signal for the frequency modulation, the frequency shifts corresponding to such large overshoots are too great to be included in the transmission band of the apparatus, that is, the band of frequencies that can be magnetically recorded and reproduced, so that the recording and reproducing of the video signal cannot be effected with a linear characteristic. In order to bring the frequency modulated video signal, as recorded and reproduced, within the allowable transmission band, it is well known to provide the recording section of the apparatus with a clip circuit for clipping the pre-emphasized video signal at a predetermined level, particularly in respect to the white level, so that those overshoots which would result in over-modulation are clipped or removed prior to the frequency modulation. In the case of such limiting of the pre-emphasized video signal in the recording operation, when the video signal is processed in a de-emphasis circuit after demodulation during the reproducing operation, it is not possible to obtain precisely the original video signal owing to waveform distortions occurring at the locations of the limited or clipped overshoot portions.